Pump, cooler, and electronic device

ABSTRACT

A pump includes a pump housing, a rotary unit, and a motor to rotate the rotary unit. The pump housing has a heat receiving surface thermally coupled to a CPU, a pump chamber, and three mounting portions provided around the pump chamber. The rotary unit is provided in the pump chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority of Japanese Patent Application No. 2004-133534, filed Apr. 28, 2004, the entire contents of which are incorporated herein by reference.

BACKGROUND

1. Field

The embodiments of the invention generally relate to liquid cooling systems and more particularly to a pump in a liquid cooling system to cool heat generating units, such as a central processing unit (CPU), using a liquid coolant.

2. Description of the Related Art

With enhancement in processing speed and multi-functionality, CPUs can generate a very large amount of heat during operation (i.e., operating heat), and may require cooling to maintain steady operation.

Heatsinks are used as a cooler to cool a CPU. The heatsink may have an electric fan to blow cool air over the CPU, and a casing to accommodate the electric fan. The casing has a heat receiving surface thermally coupled to a heat generating unit, and at least three mounting portions. The heatsink is secured so that the heat receiving surface and the CPU are thermally coupled to each other. One such heatsink is disclosed in Japan Pat. Appln. KOKAI Publication No. 2002-353670.

As discussed previously, CPUs used in electronic devices have the tendency to increase the amount of operating heat with enhancements in processing speed and multi-functionality. In recent years, by way of a countermeasure to such heat generation, electronic devices have been put into practice with a generally known liquid cooling type of cooler that cools a CPU by using a liquid coolant with a specific heat significantly greater than air.

Liquid cooling type coolers with a contact-heat-exchange pump have been proposed. The contact-heat-exchange pump has a flat box-like pump casing with a heat receiving surface thermally coupled to a heat-generating electronic component; a ring-like impeller having a rotor magnet provided in an inner circumference; and a motor stator provided in an inner circumference side of the rotor magnet. One such contact-heat-exchange pump is disclosed in, for example, Japan Pat. No. 3452059.

In the contact-heat-exchange pump of the type disclosed in the Japan Pat. No. 3452059, mounting portions are individually provided in four corner portions of a pump housing. As such, the contact-heat-exchange pump is secured at the four mounting portions such that a heat receiving surface is thermally coupled to a CPU.

However, in a configuration having many mounting portions, the mounting of a pump is likely to be intricate and it would be good if it's easier to accomplish.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.

FIG. 1 is a perspective view showing a portable computer according to an embodiment of the invention;

FIG. 2 is a perspective view of the portable computer shown in FIG. 1, as viewed from the side of exhaust openings of a first housing;

FIG. 3 is a plan view of a cooler housed in the first housing;

FIG. 4 is an exploded perspective view of a pump; and

FIG. 5 is a cross-sectional view taken along line V-V of FIG. 3.

DETAILED DESCRIPTION

In one embodiment of the invention, a pump is provided including a pump housing, a rotary unit, and a motor. The pump housing has a heat receiving surface thermally coupled to a heat generating unit, a pump chamber, and three mounting portions. The rotary unit is provided in the pump chamber. The motor is coupled to the rotary unit to rotate it within the pump chamber to pump liquid coolant. At least one of the three mounting portions is located near a middle portion of a side of the pump housing.

In another embodiment of the invention, a liquid cooling system is provided including a heat dissipation portion; a circulation path coupled to the heat dissipation portion; and a pump coupled to the circulation path and a heat generating unit. The pump is to transfer heat from the heat generating unit into a liquid coolant and to circulate the liquid coolant in the circulation path. The pump includes a pump chamber accommodate a rotary unit to circulate coolant in the circulation path; a motor coupled to the rotary unit to rotate it; and three mounting portions at least one of which is located near a middle portion of a side of the pump.

In another embodiment of the invention, an electronic device is provided with a housing and a cooler mounted in the housing. The housing has a heat generating unit and the cooler is used to cool the heat generating unit. The cooler includes a heat dissipation portion, a circulation path thermally coupled to the heat dissipation portion, and a pump coupled to the circulation path and the heat generating unit. The pump is used to circulate a coolant with the circulation path. Amongst other elements, the pump includes three mounting portions to secure the pump to the housing of the electronic device.

Embodiments of the invention are described below with reference to FIGS. 1 to 5.

FIGS. 1 and 2 show an electronic device such as a portable computer 1. The portable computer 1 has a computer main body 2 and a display unit 3. The computer main body 2 has a flat box-like first housing 10.

The first housing 10 has a bottom wall 11 a, an upper wall 11 b, a front wall 11 c, left and right sidewalls 11 d and 11 e, and a rear wall 11 f.

Referring to FIG. 1, the upper wall 11 b has a palm rest 12 and a keyboard mounting portion 13. The keyboard mounting portion 13 is provided in a portion of the upper wall which is behind the palm rest 12. A keyboard 14 is mounted in the keyboard mounting portion 13. The front wall 11 c, the left and right sidewalls 11 d and 11 e, and the rear wall 11 f form a peripheral wall along the periphery of the first housing 10.

With reference to FIG. 2, a plurality of exhaust openings 15 are formed in the peripheral wall of the first housing 10, such as the rear wall 11 f. The exhaust openings 15 are aligned in the width direction of the first housing 10.

Referring again to FIG. 1, the display unit 3 has a flat box-like second housing 20 and a display panel 21 such as an LCD (liquid crystal display) panel a. The LCD panel 21 is accommodated in the second housing 20. The LCD panel 21 has a screen 21 a that displays images. The screen 21 a is exposed outwardly of the second housing 20 through an opening portion 22 formed on a front plane of the second housing 20.

The second housing 20 is supported by a hinge (not shown) to a rear end portion of the first housing 10. As such, the display unit 3 is pivotally movable between a closed position and an open position. The closed position is a position in which the display unit 3 is folded from the upper portion such as to cover the palm rest 12 and the keyboard 14. The open position is a position where the display unit 3 stands upright exposing the palm rest 12, the keyboard 14, and the screen 21 a.

Referring now to FIG. 3, a printed circuit board 30 is accommodated in the first housing 10. More specifically, as is shown in FIG. 5, the printed circuit board 30 is disposed parallel with the bottom wall 11 a of the first housing 10. A central processing unit (CPU) 31, a heat generating unit, is mounted on an upper face of the printed circuit board 30. The CPU 31 constitutes a microprocessor, which serves as a central component of the portable computer 1.

The CPU 31 has a base substrate 32 and a planarly square integrated circuit (IC) chip 33 disposed in a central portion of the upper face of the base substrate 32. With enhancement in properties of the CPU 24, such as processing speed and multi-functionality, the IC chip 33 generates a very large amount of heat during operation, requiring that it be cooled in order to maintain a stabilized operation.

As is shown in FIG. 3, the portable computer 1 has a liquid-cooling type cooler or cooling system 40 for cooling the CPU 31 by using a liquid coolant such as antifreeze. The cooler 40 is accommodated in the first housing 10. The cooler 40 may include components such as a pump 100 concurrently serving as a heat receiving portion and a heat exchanger; a heat dissipation portion 50; a circulation path 60; and an electric fan 70.

As shown in FIGS. 3-5, the pump 100 lets a liquid coolant forcedly circulate and flow in the circulation path 60. The pump 100 may include a pump housing 101 concurrently serving as a heat receiving portion; a rotary unit 102; a motor 103 having a rotor 103 a and a stator 103 b; and a control board 104.

As shown in FIGS. 4-5, the pump housing 101 may include a housing body 110, a heat receiving portion such as a heat receiving plate 111, and a cover 112. The pump housing 101 may be shaped like a flat box to form a substantially plano-square that is larger than the CPU 31. The pump housing generally has four corner portions 101 a, 101 b, 10 c, and 101 d. The corner portion 101 d may differ from the others as it may be squared or cut off as is illustrated in FIG. 3.

In one embodiment of the invention, the pump housing 101 is assumed to be formed such that the center of gravity thereof essentially matches a center O_(H) of the pump housing 101. Additionally, it is assumed that the center OH of the pump housing 101 is at an intersection between a perpendicular line extending through the center of a substantially square upper face of the pump housing 101 and a plane extending through a thickness-wise center of the pump housing 101 (see FIGS. 3 and 5).

The housing mainbody 110 has a recess portion 113 opening downward at a bottom or lower face. The top or upper face of the housing mainbody 110 has a stator-accommodating recess portion 115 for accommodating the stator 103 b (see FIG. 5) and a control-board accommodation recess portion (not shown) to accommodate the control board 104.

The heat receiving plate 111 is mounted from the lower portion to provide a liquid-tight seal over an opening end of the recess portion 113 of the housing body 110. An O-ring 123 may be provided between the housing body 110 and the heat receiving plate 111. The cover 112 is mounted from the upper portion to the housing body 110 to cover over the openings of the stator-accommodating recess portion 115 and the control-board accommodation recess portion (not shown). The heat receiving plate 111, the housing body 110, and the cover 112 are secured together with a plurality of screws 106. The cover 112 covers the stator 103 b and the control board 104, and concurrently, is used to restrain leakage, evaporation, and the like of the liquid coolant that is used in the pump housing 101. However, the cover 112 need not be provided if unnecessary.

When mounting the pump, the heat receiving plate 111 opposes the CPU 31. A lower face of the heat receiving plate 111 may provide a flat heat receiving surface 120. The heat receiving plate 111 is preferably formed out of a high thermal conductivity material, such as copper, aluminum, or an aluminum alloy.

Within the recess portion 113, a ring-like partition wall 117 is provided that is integrally formed with the housing body 110. The interior of the pump housing 101, a region surrounded by the recess portion 113 of the housing body 110 and the upper face of the heat receiving plate 111, is partitioned by the partition wall 117 into a pump chamber 118 and a reservoir tank 119 to contain liquid coolant. In positions opposing the corner portion 101 d, the partition wall 117 has first and second communication openings (not shown) for communication between the pump chamber 118 and the reservoir tank 119.

In one embodiment of the invention, the pump chamber 118 is provided near the side of the corner portion 101 b. The corner portion 101 b and the corner portion 101 d are point-symmetric with respect to the center O_(H) of the pump housing 101. More specifically, the substantially plano-circular pump chamber 118 is off-center with respect to the center O_(H) of the pump housing 101 in a direction from the corner portion 101 d. The reservoir tank 119 surrounds the pump chamber 118 from the corner portions 101 a, 10 c, and 101 d.

In the corner portion 101 d, the housing body 110 may also have a discharge pipe 131 as a first communication portion and a suction pipe 132 as a second communication portion. The discharge pipe 131 is used for intercommunication between the interior of the pump housing 101 and the exterior of the pump housing 101. The suction pipe 132 is used for intercommunication between the interior of the pump housing 101 and the exterior of the pump housing 101.

The discharge pipe 131 and the suction pipe 132 are horizontally disposed spaced apart from each other. A downstream end of the discharge pipe 131 and an upstream end of the suction pipe 132 protrude outwardly through the housing body 110.

A first communication piping 133 a is provided between an upstream end of the discharge pipe 131 and a first communication opening of the partition wall 117. A second communication piping 133 b is provided between a downstream end of the suction pipe 132 and a second communication opening of the partition wall 117. The first communication piping 133 a and the second communication piping 133 b may be integrated into one unit and thereby constitute a communication piping unit 133.

The upstream end of the discharge pipe 131 communicates with the pump chamber 118 through the first communication piping 133 a and the first communication opening. The downstream end of the suction pipe 132 communicates with the pump chamber 118 through the second communication piping 133 b and the second communication opening. A gas-liquid separation opening 134 may be provided to the second communication piping 133 b such as illustrated in FIGS. 3-4. In this case, when the position of the pump housing 101 changes to any direction, the gas-liquid separation opening 134 is positioned so that it is maintained under a liquid level of liquid coolant stored in the reservoir tank 119.

The rotary unit 102 agitates the liquid coolant in the pump chamber 118 to transfer the liquid coolant from the interior of the pump housing 101 to the exterior of the pump housing 101 by way of the circulation path 60. The rotary unit 102 acts as an impeller, for example, and may be referred to as such. The rotary unit 102 is accommodated in the pump chamber 118. The rotary unit 102 may be formed out of a resin product, and has a discoidal mainbody portion 102 b and a rotation axis 102 a. The rotation axis 102 a is formed integrally with the mainbody portion 102 b to pass through a center O_(I) of the mainbody portion 102 b. The mainbody portion 102 b has a plurality of blades on a face that opposes the heat receiving plate 111. The rotation axis 102 a is disposed to be positioned between an upper wall of the housing body 110 and the heat receiving plate 111 in such a manner as to extend thereacross, whereby the rotary unit 102 is rotatably supported by the upper wall of the housing body 110 and the heat receiving plate 111.

The motor 103 is coupled to and rotatably drives the rotary unit 102. The motor 103 includes a rotor 103 a that has a magnet magnetized through multiple positive polarities and multiple negative polarities and has a ring-like shape. The rotor 103 a is accommodated in the pump chamber 118 to rotate while being secured coaxially to an upper face of the rotary unit 102.

As described above, the pump chamber 118 is off-centered with respect to the center O_(H) of the pump housing 101. In which case, the rotary unit 102 to be disposed in the pump chamber 118 is also off-centered with respect to the center O_(H) of the pump housing 101. Specifically, the center O_(I) of the mainbody portion 102 b of the rotary unit 102 is offset from the center O_(H) Of the pump housing 101. More specifically, a perpendicular line L1 (matching the axis line of the rotation axis 102 a) extending through the center O_(I) of the mainbody portion 102 b of the rotary unit 102 is offset with respect to a perpendicular line L2 extending through the center OH of the pump housing 101 (see FIG. 5).

The motor 103 further includes a stator 103 b which is accommodated in the stator-accommodating recess portion 115. The motor 103 may oppose the rotor 103 a through the upper wall of the housing body 110. As such, the stator-accommodating recess portion 115 is provided in a position to correspond to the rotor 103 a. That is, the stator-accommodating recess portion 115 is provided near the corner portion 101 b in one embodiment of the invention. The control-board accommodation recess portion may be provided in a position to avoid the stator-accommodating recess portion 115.

In addition, the stator-accommodating recess portion 115 is formed within the confines of the rotor 103 a. More specifically, the stator 103 b is coaxially accommodated inside the rotor 103 a through the upper wall of the housing body 110. The stator 103 b is electrically connected to the control board 104.

Energization of the stator 103 b may be performed periodically, such as at the time of power-on of the portable computer 1, for example. By the energization, a rotation magnetic field occurs in the circumferential direction of the stator 103 b to which the rotor 103 a is magnetically coupled. As a consequence, a rotating torque along the circumferential direction of the rotary unit 102 is generated between the stator 103 b and the rotor 103 a, whereby the rotary unit 102 is rotated.

As illustrated in FIG. 3, the pump housing 101 has three mounting portions 151, 152, and 153 that are used to mount the pump 100 to the first housing 10. The three mounting portions 151-153 are provided around the pump chamber 118, and, more specifically, on the periphery of the pump housing 101.

To stably mount the pump 100 to the first housing 10 at the three mounting portions 151-153, the individual positions of the three mounting portions 151-153 are preferably set so that the center of gravity of the pump housing 101 is included in a triangular region (the triangular region shown in FIG. 3 by a two-dotted chain line connecting the three mounting portions 151-153) formed by the three mounting portions 151-153. Further, to stably mount the pump 100 to the first housing 10 at the three mounting portions 151-153, the individual positions of the three mounting portions 151-153 are set so that the center of the rotary unit 102 is included in this triangular region. In one embodiment of the invention, the individual positions of the three mounting portions 151 to 153 are set so that the center O_(H) of the pump housing 101 (which essentially matches the center of gravity of the pump housing 101, as described above) and the center O_(I) of the mainbody portion 102 b of the rotary unit 102 are also included in this triangular region.

In one embodiment of the invention, the rotary unit 102 may be provided nearer corner portion 101 b with respect to the center O_(H) of the pump housing 101. That is, the rotary unit 102 may be provided in the pump chamber 118 off-center in the direction of side 121 a. As such, the degree of spatial freedom in the pump housing 101 is greater in a region closer to side 121 c than a region closer to side 121 a.

Accordingly, the three mounting portions 151, 152 and 153 may be disposed as described below and illustrated in FIG. 3.

Among the three mounting portions 151-153, the two mounting portions 151 and 152 are positioned at end portions of the side 121 a in the respective corner portions 101 a and 101 b. Side 121 a is opposite to side 121 c with respect to the substantially plano-square heat receiving surface 120. The mounting portion 153 is positioned corresponding to a middle portion of side 121 c that is opposite side 121 a.

Referring now to FIG. 4, cutout portions 110 a and 112 a are formed respectively in a portion of the housing body 110 and the cover 112 corresponding to the corner portion 101 a to form the mounting portion 151 provided in the corner portion 101 a. Additionally, an opening portion 111 a is formed in the heat receiving plate 111 corresponding to the corner portion 101 a to further form the mounting portion 151.

Similarly, cutout portions 110 b and 112 b are formed respectively in a portion of the housing body 110 and the cover 112 corresponding to the corner portion 101 b to form the mounting portion 152 provided in the corner portion 101 b. Additionally, an opening portion 111 b is formed in the heat receiving plate 111 corresponding to the corner portion 101 b to further form the mounting portion 152 provided in the corner portion 101 b.

Cutout portions 110 c and 112 c are formed respectively in middle portions of the housing body 110 and the cover 112 corresponding to a middle portion of the side 121 c to form the mounting portion 153 provided in the position corresponding to the middle portion of side 121 c. Additionally, an opening portion 111 c is formed in the heat receiving plate 111 corresponding to the middle portion of side 121 c to further form the mounting portion 153 provided in the position corresponding to the middle portion of the side 121 c. The O-ring 123, if provided, jogs around and avoids the position of the mounting portion 153 as illustrated in FIG. 4.

The pump 100 thus configured is disposed on the printed circuit board 30 in such a manner so as to cover over the CPU 31 with the center O_(H) of the pump housing 101 being matched with a center O_(C) of the CPU 31 (which may also be the center of the IC chip 33). That is, the center O_(H) of the pump housing 101 is matched with the center O_(C) of the CPU to be concentric so that that a perpendicular line L2 extending through the center O_(H) of the pump housing 101 also extends through the center O_(C) of the CPU.

As is shown in FIG. 5, the pump housing 101 of the pump 100 is secured together with the printed circuit board 30 to the bottom wall 11 a of the first housing 10. The bottom wall 11 a has boss portions 17 in positions corresponding to the mounting portions 151-153. The boss portions 17 project upwardly from the bottom wall 11 a. The printed circuit board 30 may be overlaid on edge faces of these boss portions 17. A reinforcing plate 34 may be provided under the printed circuit board 30 adjacent to a lower face thereof to provide reinforcement.

In one embodiment of the invention, the mounting mechanism for mounting the pump 100 to the first housing 10 includes three cylindrical inserts 143, three coil springs 144, three C-rings 145, and three screws 146, for example, in addition to the mounting portions 151-153. The inserts 143 may each have a projection portion 143 a at an upper end projecting circumferentially outward in a horizontal direction. Additionally, each cylindrical insert 143 may have a groove portion 143 b formed on an outer circumferential surface of the insert in a circumferential direction.

The pump 100 is compressed against the CPU 31 and secured in that state, in the following manner. While only components of a mounting structure in the mounting portion 152 is shown in FIG. 5 and described below, it is to be understood that similar components may be used to form similar mounting structures located at the mounting portions 151 and 153.

The cylindrical insert 143 is inserted into the center of a coil spring 144. The cylindrical insert 143 with the coil spring 144 are inserted into each of the opening portions 111 a, 111 b, and 111 c of the heat receiving plate 111 so that the groove portion 143 b in each insert 143 is positioned below the heat receiving surface 120 of the pump 100. A fall-out prevention C-ring 145 is fitted into the groove portion 143 b of each insert 143. Thereby, the cylindrical insert 143 is mounted to a position corresponding to each of the mounting portions 151-153 of the pump 100 in a spring loaded state so that the coil spring 144 applies a force between the projection portion 143 a and the heat receiving plate 111.

A conductive grease (not shown) is applied on any one of an upper face of the IC chip 33 and a region corresponding to the IC chip 33 of the heat receiving surface 120. The pump is aligned and positioned so that the heat receiving surface 120 of the pump housing 101 is opposite the IC chip 33. Screws 146 are inserted into each cylindrical insert 143 and screwed into the boss portion 17 formed on the bottom wall 11 a. Thereby, the respective cylindrical inserts 143 are secured to the boss portions 17, and the pump 100 is forced against the IC chip 33 by resilience of the coil springs 144. In this manner, the IC chip 33 is thermally coupled to the heat receiving surface 120 of the pump housing 101 through the conductive grease.

As is shown in FIG. 3, the heat dissipation portion 50 has a heat-dissipation-portion mainbody 51 and multiple dissipation fins 57 thermally coupled with the heat-dissipation-portion main body 51. The heat-dissipation-portion main body 51 is configured of substantially U-shaped piping through which the liquid coolant flows. More specifically, the heat-dissipation-portion main body 51 is configured with a coolant inlet opening 54 and a coolant outlet opening (provided on an opposite side of the coolant inlet opening 54 as viewed in FIG. 3, although it is not visibly shown) to allow the coolant to flow inside. That is, one opening end of the piping serves as the coolant inlet opening 54, and the other opening end serves as the coolant outlet opening. The piping (heat-dissipation-portion main body 51) of the heat dissipation portion 50 may be consider to be a part of the circulation path 60 (which will be described below in more detail).

In one embodiment of the invention, the heat-dissipation-portion mainbody 51 is accommodated in the first housing 10 in such a manner that the substantially U-shaped piping is 90-degree rotated (horizontally inclined or positioned) with the coolant inlet opening 54 being on top and the coolant outlet opening being on the bottom. The dissipation fins 57 may be formed of a metal material, such as an aluminum alloy or copper material, which has good thermal conductivity. The dissipation fins 57 may be formed to have a rectangular plate shape. The individual dissipation fins 57 are disposed parallel to one another with a spacing being maintained from one another. The individual dissipation fins 57 may be soldered to the heat-dissipation-portion main body 51.

The heat dissipation portion 50 is accommodated in the first housing 10, where the dissipation fins 57 are positioned opposite the exhaust openings 15 of the first housing 10. A pair of brackets 58 may be soldered to the heat dissipation portion 50. The brackets 58 may each be secured with a screw to a boss portion (not shown) projecting from the bottom wall 11 a of the first housing 10. Thereby, the heat dissipation portion 50 can be secured to the bottom wall 11 a of the first housing 10.

The circulation path 60 has first piping 61, second piping 62, and the piping of the heat-dissipation-portion main body 51 in the heat dissipation portion 50. That is, the heat-dissipation-portion main body 51 serves concurrently as being the heat dissipation portion 50 and the circulation path 60. The first piping 61 connects between the discharge pipe 131 of the pump 100 and the coolant inlet opening 54 of the heat dissipation portion 50. The second piping 62 connects between the suction pipe 132 of the pump 100 and the coolant outlet opening of the heat dissipation portion 50. Thereby, the liquid coolant passes through the first and second piping 61 and 62 to circulate between the pump 100 and the heat dissipation portion 50.

The electric fan 70 blows cooling air onto and through the heat dissipation portion 50, and is disposed anterior to the heat dissipation portion 50. The electric fan 70 has a fan casing 71 and a centrifugal impeller 72 accommodated in the fan casing 71. The fan casing 71 has an outlet opening 71 a which discharges cooling air. The outlet opening 71 a is connected to the heat dissipation portion 50 through a duct 73.

The impeller 72 is driven by a motor (not shown). The impeller 72 may be driven at power-on of the portable computer 1 or when the temperature has reached a predetermined level, for example. Cooling air is supplied from the outlet opening 71 a of the fan casing 71 to the heat dissipation portion 50.

Operation of the cooler or cooling system 40 is now described.

The IC chip 33 of the CPU 31 generates heat during use of the portable computer 1. The heat generated by the IC chip 33 transfers to the pump housing 101 through the heat receiving surface 120 of the pump 100. The recess portion 113 (the pump chamber 118 and the reservoir tank 119) of the pump housing 101 is filled with the liquid coolant, so that the liquid coolant absorbs much of the heat transferred to the pump housing 101.

Energization to the stator 103 b of the motor 103 may periodically occur such as in synchronous with the power-on of the portable computer 1. Thereby, a rotating torque occurs between the stator 103 b and the rotor 103 a, whereby the rotor 103 a is rotated with the rotary unit 102. Upon rotation of the rotary unit 102, the liquid coolant in the pump chamber 118 is pressurized thereby to be discharged from the discharge pipe 131, and concurrently, is led into the heat dissipation portion 50 from the coolant inlet opening 54 through the first piping 61. The liquid coolant from the coolant inlet opening 54 is heated by heat exchange in the pump housing 101 and flows out through the coolant outlet opening to the heat dissipation portion 50, where the heat of the IC chip 33 absorbed by the liquid coolant is transferred to the dissipation fins 57.

Upon rotation of the impeller 72 of the electric fan 70 during use of the portable computer 1, cooling air flows to the heat dissipation portion 50 from the outlet opening 71 a of the fan casing 71. The cooling air passes through between the dissipation fins 57 being adjacent to one another. Thereby, components such as the dissipation fins 57 and the heat-dissipation-portion main body 51 are cooled. Then, much of the heat having transferred to the dissipation fins 57, the heat-dissipation-portion main body 51, and the like is transferred to and carried on the cooling air flow, and dissipated outside of the first housing 10 through the exhaust opening 15.

The liquid coolant cooled in the heat dissipation portion 50 is guided into the suction pipe 132 of the pump housing 101 through the second piping 62. The liquid coolant is returned from the suction pipe 132 to the reservoir tank 119. The liquid coolant thus returned to the reservoir tank 119 again absorbs heat from the IC chip 33 while liquid coolant is sucked into the pump chamber 18. In iteration of the operation cycle, heat of the IC chip 33 is progressively transferred to the heat dissipation portion 50, transferred to and carried on the cooling air flow passing through the heat dissipation portion 50, and then dissipated to outside of the first housing 10.

As described above, the pump 100 has the pump housing 101 with three mounting portions 151-153. As such, the number of the mounting portions in the pump 100 is less than that in a conventional pump, so that the pump 100 can be easily mounted.

Further, the individual positions of the three mounting portions 151-153 may be set at corners of a triangular region that includes the center O_(I) of the rotary unit 102. As such, with the pump housing 101 secured at the mounting portions 151-153, vibrations resulting from the rotation of the rotary unit 102 can be optimally received. Consequently, even with only three mounting portions, the pump 100 can be secured in a stable state so that the pump 100 can be mounted to the portable computer 1 or the like without impairing pump performance.

Further, the individual positions of the three mounting portions 151-153 may be set at corners of a triangular region that includes the center O_(H) of the pump housing 101. As such, with the pump housing 101 secured at the mounting portions 151-153, the pump housing 101 can be secured in a stable state. Consequently, the pump 100 can be mounted to the portable computer 1 or the like without impairing pump performance.

Further according to another embodiment of the invention, the center O of the rotary unit 102 is offset from the center O_(H) of the pump housing 101 in the pump 100. As such, the pump 100 can be secured to the printed circuit board 30 so that the center O_(H) of the pump housing 101 substantially matches the center O_(C) of the IC chip 33. Thereby, the pump housing 101 can be secured in a stable state and a heat generating unit, such as the IC chip 33, can be optimally cooled.

In the pump chamber 118, as the distance from the center O_(I) of the rotary unit 102 increases, the liquid coolant flows faster. To cause the liquid coolant to absorb a greater amount of heat from the heat generating unit, such as the IC chip 33, the center of the heat generating unit can be positioned offset from the center O_(I) where the liquid coolant flows faster and opposed under the pump chamber with the pump housing 101 being interposed.

Accordingly in one embodiment of the invention, the pump 100 is employed and secured onto the printed circuit board 30 so that the center O_(H) of the pump housing 101 substantially matches the center O_(C) of the IC chip 33. Thereby, the IC chip 33 can be set to oppose, with the pump housing 101 being interposed, the position where the liquid coolant flows fast. Further, since the center O_(H) of the pump housing 101 substantially matches the center O_(C) of the IC chip 33, the pump 100 can be secured in a stable position on the print circuit board 30.

Further in another embodiment of the invention, since the center O_(I) of the rotary unit 102 in the pump 100 is offset from the center O_(H) of the pump housing 101, the degree of spatial freedom in the region closer to the side 121 c is greater than the region closer to the side 121 a. Accordingly, the two mounting portions 151 and 152 are provided at end portions of side 121 a of the heat receiving surface 120. Additionally, the third mounting portion 153 is provided at the middle portion of side 121 c. Thereby, the mounting portions 151-153 of the pump 100 are disposed to use the spacing effectively. Consequently, the pump 100 can be miniaturized while the performance required of the pump is secure. Alternatively, in embodiments of the invention configured with the reservoir tank 119 in the pump housing 101, a larger capacity of the reservoir tank 119 can be secured with the mounting portions 151-153 of the pump 100 being disposed to use the spacing effectively.

Further, since the center O_(I) of the rotary unit 102 is offset from the center O_(H) of the pump housing 101, the degree of spatial freedom is relatively high in the vicinity of the ends of side 121 c. As such, the discharge pipe 131 and the suction pipe 132, which are used for communication between the interior of the pump housing 101 and the exterior of the pump housing 101, may be provided at one end portion of side 121 c. Thereby, the pump 100 can have the discharge pipe 131 and the suction pipe 132 disposed to use space effectively. Consequently, while the performance required for pumps is secure, the pump 100 can be miniaturized.

According to an embodiment of the invention, the cooler 40 has a pump 100 with three mounting portions 151-153. Consequently, in comparison with a conventional pump, assembling of pump 100 is easier, and hence the mounting time (assembly time) can be reduced.

According to one embodiment of the invention, the pump 100 is secured to the first housing 10 of the portable computer 1 at the three mounting portions 151 to 153. Consequently, in comparison with a conventional pump, the pump mounting time can be reduced. Additionally, the CPU 31 typically has a very large number of pins (electrical connection portions), making wirings intricate. By mounting the pump 100 secured at the three portions, wirings can be more easily routed in comparison with a conventional pump. Further, the number of boss portions 17 can be reduced when using pump 100 and the three mounting portions in comparison with a conventional pump. Consequently, a higher density can be implemented in the first housing 10.

The application of the pump is not limited to electronic devices, such as the portable computer, or the cooler mounted therein. The pump can be broadly used in any one of various other devices. Further, the electronic device is not limited to a portable computer. The electronic device may be applied to any one of other devices that has a heat generating unit and a cooler to cool the heat generating unit.

Additional modifications to embodiments of the invention will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. 

1. A pump comprising: a pump housing including a heat receiving surface thermally coupled to a heat generating unit, a pump chamber to receive liquid coolant, and three mounting portions at least one of which is located near a middle portion of a side of the pump housing; a rotary unit in the pump chamber; and a motor coupled to the rotary unit, the motor to rotate the rotary unit to pump liquid coolant in the pump chamber.
 2. A pump according to claim 1, wherein the three mounting portions are positioned so that a center of gravity of the pump housing is included within a triangular region formed by the three mounting portions.
 3. A pump according to claim 1, wherein the three mounting portions are positioned so that a center of the rotary unit is included within a triangular region formed by the three mounting portions.
 4. A pump according to claim 1, wherein a center of the rotary unit is offset from a center of the pump housing.
 5. A pump according to claim 3, wherein the center of the rotary unit is offset from a center of the pump housing.
 6. A pump according to claim 1, wherein the other two of the three mounting portions are provided in positions corresponding to end portions of an opposite side of the pump housing.
 7. A pump according to claim 6, wherein the three mounting portions are positioned to form a triangular region to securely fasten the pump to a housing of an electronic device.
 8. A pump according to claim 6, wherein the pump housing further includes a reservoir tank to hold liquid coolant, and the three mounting portions are positioned to form a triangular region to increase a capacity of the reservoir tank.
 9. A pump according to claim 1, wherein the heat receiving surface of the pump housing has a pair of sides opposing each other and is centered over a center of the heat generating unit with respect to the center of the pump housing, the rotary unit is positioned in the pump chamber off-center toward one of the pair of sides to more quickly flow liquid coolant over the center of the heat generating unit.
 10. A pump according to claim 1, wherein the three mounting portions allow the pump to be more quickly mounted.
 11. A pump according to claim 1, wherein the pump housing further has a communication portion to communicate liquid coolant between an interior of the pump housing and an exterior of the pump housing.
 12. A liquid cooling system comprising: a heat dissipation portion; a circulation path coupled to the heat dissipation portion; and a pump coupled to the circulation path and a heat generating unit, the pump to transfer heat from the heat generating unit into a liquid coolant and circulate the liquid coolant in the circulation path, the pump including a pump chamber to accommodate a rotary unit to circulate the coolant in the circulation path a motor coupled to the rotary unit to rotate it, and three mounting portions at least one of which is located near a middle portion of a side of the pump.
 13. A liquid cooling system according to claim 12, wherein the three mounting portions are positioned so that a center of gravity of the pump housing is included within a triangular region formed by the three mounting portions.
 14. A liquid cooling system according to claim 12, wherein the three mounting portions are positioned so that a center of the rotary unit is included within a triangular region formed by the three mounting portions.
 15. A liquid cooling system according to claim 12, wherein the three mounting portions are positioned to form a triangular region to securely fasten the pump to a housing of an electronic device.
 16. A liquid cooling system according to claim 12, wherein the pump housing further includes a reservoir tank to hold liquid coolant, and the three mounting portions are positioned to form a triangular region to increase a capacity of the reservoir tank.
 17. A liquid cooling system according to claim 12, further comprising: an electric fan located adjacent the heat dissipation portion, the electric fan to blow cooling air towards the heat dissipation portion.
 18. An electronic device comprising: a housing having a heat generating unit; and a cooler mounted in the housing to cool the heat generating unit, the cooler including a heat dissipation portion, a circulation path thermally coupled to the heat dissipation portion, and a pump coupled to the circulation path and the heat generating unit, the pump to circulate a coolant with the circulation path, the pump including a pump housing having a heat receiving surface thermally coupled to the heat generating unit, a pump chamber to pressurize the coolant, a rotary unit in the pump chamber, the rotary unit to transfer the coolant into and out of the circulation path; a motor coupled to the rotary unit, the motor to rotate the rotary unit to transfer coolant, and three mounting portions to secure the pump to the housing.
 19. An electronic device according to claim 18, wherein the pump housing of the pump further includes a reservoir tank to hold liquid coolant, and the three mounting portions of the pump are positioned to form a triangular region to increase a capacity of the reservoir tank.
 20. An electronic device according to claim 18, wherein the cooler further includes an electric fan located adjacent the heat dissipation portion, the electric fan to blow cooling air towards the heat dissipation portion. 